In the 1960s, with just 30 pairs remaining, conservation efforts succeeded in increasing the population of the Spanish imperial eagle by a considerable amount. However, since 1994, the population has been allowed to decline again to just 160 pairs. There are several causes of this decline: habitat fragmentation due to deforestation for agricultural land and timber has disturbed breeding grounds, intentional poisoning on hunting reserves to reduce natural predators of game species, lead shot poisoning as a result of ingestion of game killed with bullets, and electrocution on power cables (2). Approximately 80% of eagles killed on power lines are female, causing a greater impact on this monogamous species than if equal numbers of males and females were killed (10).
The Spanish imperial eagle relies mainly on rabbits as prey, and following drops in rabbit abundance due to shooting and disease, food supplies have been limited causing reduced breeding success (2) (11).